A service evaluation of a Hospital In-reach Service for people who are homeless in South England

Background

Homelessness has increased dramatically in the last decade, with an estimated 165% increase in rough sleeping alone in England since 2010. People experiencing homelessness can often have what is referred to as the tri-morbidity; mental health, substance and or alcohol misuse and physical health problems. Hospital admission presents a potential point of intervention to address the health problems people have been experiencing, to link them in with services and as a bridge to housing. This service evaluation explored the role of a Hospital In-reach Service team for safer hospital discharge.

Methods

A qualitative in-depth interview study was conducted with six participants related to a Hospital In-reach Service team in South England. The interviews were transcribed, and analysed following Burnard's fourteen stage method. The ethical approval was obtained from Brighton and Sussex Medical School Research Governance and Ethics Committee (ER/BSMS4284/2).

Results

Three key themes were identified; the role of the Hospital In-reach Service team, barriers to, and facilitators for advocating patients' needs. The results indicate that the service team works incredibly well, building strong and trusting relationships with patients, community and hospital teams, taking a holistic approach to patient care. However, the structural discrimination against this patient group is reiterated in this study. Despite progress, there are still problems with non-specialist staff understanding this patient group's needs.

Conclusions

There is a need for clarification within Adult Social Care regarding the distribution of responsibility between hospital and community social work teams. There also appears to be a need for expansion of training for non-specialist service staff, including ward staff, discharge teams and social workers. In-reach housing services and expansion of the service team would be invaluable

Key messages

Hospital In-reach Service team in South England works incredibly well taking a holistic approach to patient care. Clarification in role of hospital and community social work teams is required for better management of this issue.

De novo hepatic steatosis drives atherogenic risk in liver transplantation recipients

Nonalcoholic fatty liver disease is associated with cardiovascular disease (CVD) in the general population. Despite a high prevalence of de novo hepatic steatosis after liver transplantation (LT), there are no data exploring the association between hepatic steatosis after LT and atherogenic risk. The aim of the study was to explore the impact of hepatic steatosis on serum atherogenic markers in liver transplantation recipients (LTRs). Biomarkers of CVD risk were compared in 89 LTRs with no known history of dyslipidemia, ischemic heart disease, or graft cirrhosis. To avoid potential confounders, LTRs on oral hypoglycemic agents, exogenous insulin, corticosteroids, or lipid-lowering therapy were excluded. Only patients for whom histological assessment was available after LT were included in the study. Thirty-five LTRs had de novo hepatic steatosis after LT, whereas 54 did not. Both cohorts were similar with regards to age, sex, ethnicity, and follow-up from LT. Additionally, the traditional lipid profile was similar between the 2 cohorts. LTRs with hepatic steatosis had higher serum concentrations of small-dense low-density lipoprotein cholesterol (sdLDL-C; 34.8 ± 16.9 versus 22.7 ± 11.2 mg/dL; P < 0.001), sdLDL-C to low-density lipoprotein cholesterol ratio (32.6 ± 11.6 versus 24.6 ± 10.2; P < 0.01), small-dense low-density lipoprotein particle concentration (sdLDL-P; 770 ± 440 versus 486 ± 402 nmol/L; P < 0.01), very low density lipoprotein particle concentration (VLDL-P; 7.90 ± 7.91 versus 3.86 ± 3.18 nmol/L; P < 0.01), and very low density lipoprotein size (VLDL-size; 51.9 ± 6.4 versus 48.7 ± 6.3 nm; P = 0.06). LTRs with hepatic steatosis had higher serum insulin concentrations (27.8 ± 41.8 versus 11.7 ± 7.8 uU/mL; P < 0.01) but similar fasting glucose and hemoglobin A1c. Steatosis grade was directly related to sdLDL-C, sdLDL-P, insulin, VLDL-P, and VLDL-size. In multivariate analysis, the association between steatosis grade and sdLDL-C (β = 0.03; P = 0.029), VLDL-size (β = 0.316; P = 0.04), and low-density lipoprotein particle size (β = -0.27; P = 0.05) was independent of sex, body mass index, age, diabetes mellitus, time from transplant, and indication for LT. In conclusion, de novo hepatic steatosis after LT is associated with atherogenic lipoproteins and independent of traditional CVD risk factors.

Severity of nonalcoholic fatty liver disease and progression to cirrhosis are associated with atherogenic lipoprotein profile

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is associated independently with increased cardiovascular mortality. Although NAFLD is associated with dyslipidemia, it is not clear whether recently identified markers of cardiovascular risk indicate liver disease progression in patients with histologically confirmed NAFLD. We evaluated an extensive panel of serum markers of cardiovascular risk in nondiabetic patients with histologically proven NAFLD.

METHODS

We performed a case-control study in which we compared serum levels of laboratory markers of cardiovascular risk among 81 nondiabetic subjects with histologically confirmed NAFLD vs lean (N = 81) and obese (N = 81) individuals without NAFLD (based on liver fat score, controls). For ex vivo studies, liver tissues were obtained from subjects undergoing elective cholecystectomy or from a tissue repository.

RESULTS

Subjects with NAFLD had increased serum levels of insulin, triglycerides, and apolipoprotein B; increased size and concentration of very large density lipoprotein particles; increased concentrations of low-density lipoprotein (LDL) particles and small dense LDL (sdLDL) cholesterol, and an increased percentage of sdLDL, compared with controls. Although nonalcoholic steatohepatitis was associated with a worse profile of serum atherogenic markers than NAFLD, these differences did not reach statistical significance. Despite hyperinsulinemia, triglyceride and apolipoprotein B levels, concentrations of LDL particles and LDL cholesterol, and sdLDL-related parameters decreased significantly in patients with cirrhosis. Ex vivo studies showed that patients with NAFLD had increased sensitivity of hepatic triglyceride levels and cholesterol synthesis to insulin, and that sensitivity increased the development of cirrhosis.

CONCLUSIONS

Atherogenic dyslipidemia is related to increased insulin-induced hepatic lipid synthesis in patients with NAFLD. Reduced dyslipidemia in patients with cirrhosis is associated with increased insulin resistance and possibly failed lipid synthesis.

Evolution of serum atherogenic risk in liver transplant recipients: Role of lipoproteins and metabolic and inflammatory markers

Although cardiovascular disease (CVD) is the leading cause of long-term mortality in liver transplant recipients (LTRs), the role of recently identified biomarkers of CVD risk in liver transplantation is unknown. We aimed to evaluate an extensive CVD risk profile in LTRs. Markers of CVD risk in 65 LTRs with no known history of diabetes mellitus (DM), dyslipidemia, or ischemic heart disease were compared to age-, sex-, and body mass index (BMI)-matched controls with no chronic medical disease. LTRs on corticosteroids or those with graft cirrhosis (GC) were excluded. The effect of calcineurin inhibitors on the CVD risk profile was separately analyzed in LTRs receiving either tacrolimus (Tac) or cyclosporine A (CsA). To evaluate the impact of GC, a comparison was made between LTRs with and without GC. Non-DM LTRs were matched to controls with respect to age, sex, and BMI. LTRs had similar serum high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and total cholesterol in comparison with BMI-matched controls. Proatherogenic small-dense (sd) LDL-C (33.6 ± 14 versus 25.9 ± 9.9 mg/dL; P < 0.001) and %sdLDL-C (30% ± 10% versus 26.4% ± 9%; P = 0.02) were significantly higher in LTRs. In comparison with controls, LTRs had higher apolipoprotein B (apoB; 98 ± 37 versus 88 ± 24 mg/dL; P < 0.01), very low density lipoprotein-particle concentration (VLDL-P; 7.7 ± 6.7 nmol/L versus 3.2 ± 9.1 nmol/L; P < 0.001), and VLDL size (51.1 ± 6.6 versus 46.5 ± 6.9 nm; P < 0.001). In LTRs, VLDL size and VLDL-P were directly related to serum CsA levels (r = 0.53, P = 0.09, and r = 0.63, P < 0.01, respectively) but not to Tac levels. In comparison with controls, LTRs had significantly lower total serum high-density lipoprotein-particle concentration. In comparison with those with preserved graft function, LTRs with GC had lower levels of serum atherogenic markers characterized by low sdLDL-C, apoB, triglycerides, LDL-C, and total cholesterol. In conclusion, LTRs have a proatherogenic lipoprotein profile that is not captured with a traditional lipid panel, and this suggests that a detailed serum atherogenic profile is needed to truly assess CVD risk in LTRs.

Readiness for behaviour change in non-alcoholic fatty liver disease: implications for multidisciplinary care models

BACKGROUND & AIMS

Weight management is a cornerstone of treatment for overweight/obese persons with non-alcoholic fatty liver disease (NAFLD). This exploratory study sought to: (i) evaluate readiness to change weight-related behaviours; (ii) assess psychosocial characteristics that may interfere with weight loss; and (iii) evaluate how baseline psychosocial features associate with 6-month change in weight in persons with NAFLD receiving standard medical care. The purpose of this investigation was to develop hypotheses regarding relationships between psychosocial factors and weight for use in future fully powered studies and clinical interventions

METHODS

Fifty-eight overweight/obese participants with NAFLD completed baseline measures of personality, psychiatric symptoms and readiness for behaviour change and were followed up for 6 months in standard care.

RESULTS

One-third of participants (31.0%) were not interested in making weight-related behaviour changes; 58.6% were considering making a change, and 10.4% of individuals were actively working on or preparing to change. Six-month change in weight was non-significant and was not associated with baseline readiness for change. Depression, low conscientiousness and high neuroticism were associated with higher weight at 6-month follow-up with small to large effect sizes.

CONCLUSIONS

Although participants received nutritional education and guidance, very few individuals presented in the active stage of change. Although readiness for change did not predict subsequent change in weight, personality factors and psychiatric symptoms were associated with weight outcomes. Integrated multidisciplinary approaches that address psychiatric needs and provide behavioural support for weight loss may help patients with NAFLD implement sustained lifestyle changes.

Association between high-normal levels of alanine aminotransferase and risk factors for atherogenesis

BACKGROUND & AIMS

Liver disease has been associated with cardiovascular disorders, but little is known about the relationship between serum levels of alanine aminotransferase (ALT) and markers of atherogenesis. We investigated the relationship between low-normal and high-normal levels of ALT and an extended panel of cardiovascular risk factors among individuals with no known diseases in a primary care setting.

METHODS

We performed a retrospective analysis of data collected from 6442 asymptomatic patients at wellness visits to a primary care setting in central Virginia from 2010 through 2011. Serum levels of ALT were compared with levels of lipids and lipoproteins, as well as metabolic, inflammatory, and coagulation-related factors associated with risk for cardiovascular disease.

RESULTS

Serum levels of ALT were higher than 40 IU/L in 12% of subjects, and in the high-normal range (19-40 IU/L in women and 31-40 IU/L in men) in 25% of subjects. ALT level was associated with the apolipoprotein B level, concentration and particle size of very-low-density lipoproteins, concentration of low-density lipoprotein (LDL) particles (LDL-P), and percentages of small dense LDL (sdLDL) and sdLDL-cholesterol (sdLDL-C) (P < .0001 for all). A high-normal level of ALT was associated with higher levels of LDL-C, LDL-P, sdLDL-C, and sdLDL particles (P < .001 for all). These effects were independent of age, body mass index, and hyperinsulinemia. Increasing levels of ALT and fasting hyperinsulinemia (>12 μU/mL) synergized with increasing levels of triglycerides, very-low-density lipoprotein particles, LDL-P, sdLDL-C, and percentage of sdLDL-C. Levels of APOA1, high-density lipoprotein-cholesterol, and high-density lipoprotein-class 2 were associated inversely with serum level of ALT (P < .0001 for all).

CONCLUSIONS

In an analysis of asymptomatic individuals, increased serum levels of ALT (even high-normal levels) are associated with markers of cardiovascular disease.

The plasma lipidomic signature of nonalcoholic steatohepatitis

Specific alterations in hepatic lipid composition characterize the spectrum of nonalcoholic fatty liver disease (NAFLD), which extends from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). However, the plasma lipidome of NAFLD and whether NASH has a distinct plasma lipidomic signature are unknown. A comprehensive analysis of plasma lipids and eicosanoid metabolites quantified by mass spectrometry was performed in NAFL (n = 25) and NASH (n = 50) subjects and compared with lean normal controls (n = 50). The key findings include significantly increased total plasma monounsaturated fatty acids driven by palmitoleic (16:1 n7) and oleic (18:1 n9) acids content (P < 0.01 for both acids in both NAFL and NASH). The levels of palmitoleic acid, oleic acid, and palmitoleic acid to palmitic acid (16:0) ratio were significantly increased in NAFLD across multiple lipid classes. Linoleic acid (8:2n6) was decreased (P < 0.05), with a concomitant increase in gamma-linolenic (18:3n6) and dihomo gamma-linolenic (20:3n6) acids in both NAFL and NASH (P < 0.001 for most lipid classes). The docosahexanoic acid (22:6 n3) to docosapentenoic acid (22:5n3) ratio was significantly decreased within phosphatidylcholine (PC), and phosphatidylethanolamine (PE) pools, which was most marked in NASH subjects (P < 0.01 for PC and P < 0.001 for PE). The total plasmalogen levels were significantly decreased in NASH compared with controls (P < 0.05). A stepwise increase in lipoxygenase (LOX) metabolites 5(S)-hydroxyeicosatetraenoic acid (5-HETE), 8-HETE, and 15-HETE characterized progression from normal to NAFL to NASH. The level of 11-HETE, a nonenzymatic oxidation product of arachidonic (20:4) acid, was significantly increased in NASH only.

CONCLUSIONS

Although increased lipogenesis, desaturases, and LOX activities characterize NAFL and NASH, impaired peroxisomal polyunsaturated fatty acid (PUFA) metabolism and nonenzymatic oxidation is associated with progression to NASH.

High-dose ursodeoxycholic acid for the treatment of primary sclerosing cholangitis

Previous controlled trials are inconclusive regarding the efficacy of ursodeoxycholic acid (UDCA) for treating primary sclerosing cholangitis (PSC). One hundred fifty adult patients with PSC were enrolled in a long-term, randomized, double-blind controlled trial of high-dose UDCA (28-30 mg/kg/day) versus placebo. Liver biopsy and cholangiography were performed before randomization and after 5 years. The primary outcome measures were development of cirrhosis, varices, cholangiocarcinoma, liver transplantation, or death. The study was terminated after 6 years due to futility. At enrollment, the UDCA (n = 76) and placebo (n = 74) groups were similar with respect to sex, age, duration of disease, serum aspartate aminotransferase and alkaline phosphatase levels, liver histology, and Mayo risk score. During therapy, aspartate aminotransferase and alkaline phosphatase levels decreased more in the UDCA group than the placebo group (P < 0.01), but improvements in liver tests were not associated with decreased endpoints. By the end of the study, 30 patients in the UDCA group (39%) versus 19 patients in the placebo group (26%) had reached one of the pre-established clinical endpoints. After adjustment for baseline stratification characteristics, the risk of a primary endpoint was 2.3 times greater for patients on UDCA than for those on placebo (P < 0.01) and 2.1 times greater for death, transplantation, or minimal listing criteria (P = 0.038). Serious adverse events were more common in the UDCA group than the placebo group (63% versus 37% [P < 0.01]).

CONCLUSION

Long-term, high-dose UDCA therapy is associated with improvement in serum liver tests in PSC but does not improve survival and was associated with higher rates of serious adverse events.

A lipidomic analysis of nonalcoholic fatty liver disease

The spectrum of nonalcoholic fatty liver disease (NAFLD) includes a nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). The specific types and amounts of lipids that accumulate in NAFLD are not fully defined. The free fatty acid (FFA), diacylglycerol (DAG), triacylglycerol (TAG), free cholesterol (FC), cholesterol ester, and phospholipid contents in normal livers were quantified and compared to those of NAFL and NASH, and the distribution of fatty acids within these classes was compared across these groups. Hepatic lipids were quantified by capillary gas chromatography. The mean (nmol/g of tissue) DAG (normal/NAFL/NASH: 1922 versus 4947 versus 3304) and TAG (13,609 versus 128,585 versus 104,036) increased significantly in NAFLD, but FFA remained unaltered (5533 versus 5929 versus 6115). There was a stepwise increase in the mean TAG/DAG ratio from normal livers to NAFL to NASH (7 versus 26 versus 31, P < 0.001). There was also a similar stepwise increment in hepatic FC (7539 versus 10,383 versus 12,863, P < 0.05 for NASH). The total phosphatidylcholine (PC) decreased in both NAFL and NASH. The FC/PC ratio increased progressively (0.34 versus 0.69 versus 0.71, P < 0.008 for both). Although the levels for linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) remained unaltered, there was a decrease in arachidonic acid (20:4n-6) in FFA, TAG, and PC (P < 0.05 for all) in NASH. Eicosapentanoic acid (20:5n-3) and docosahexanoic acid (22:6n-3) were decreased in TAG in NASH. The n-6:n-3 FFA ratio increased in NASH (P < 0.05).

CONCLUSIONS

NAFLD is associated with numerous changes in the lipid composition of the liver. The potential implications are discussed.

A lipidomic analysis of nonalcoholic fatty liver disease

The spectrum of nonalcoholic fatty liver disease (NAFLD) includes a nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). The specific types and amounts of lipids that accumulate in NAFLD are not fully defined. The free fatty acid (FFA), diacylglycerol (DAG), triacylglycerol (TAG), free cholesterol (FC), cholesterol ester, and phospholipid contents in normal livers were quantified and compared to those of NAFL and NASH, and the distribution of fatty acids within these classes was compared across these groups. Hepatic lipids were quantified by capillary gas chromatography. The mean (nmol/g of tissue) DAG (normal/NAFL/NASH: 1922 versus 4947 versus 3304) and TAG (13,609 versus 128,585 versus 104,036) increased significantly in NAFLD, but FFA remained unaltered (5533 versus 5929 versus 6115). There was a stepwise increase in the mean TAG/DAG ratio from normal livers to NAFL to NASH (7 versus 26 versus 31, P < 0.001). There was also a similar stepwise increment in hepatic FC (7539 versus 10,383 versus 12,863, P < 0.05 for NASH). The total phosphatidylcholine (PC) decreased in both NAFL and NASH. The FC/PC ratio increased progressively (0.34 versus 0.69 versus 0.71, P < 0.008 for both). Although the levels for linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) remained unaltered, there was a decrease in arachidonic acid (20:4n-6) in FFA, TAG, and PC (P < 0.05 for all) in NASH. Eicosapentanoic acid (20:5n-3) and docosahexanoic acid (22:6n-3) were decreased in TAG in NASH. The n-6:n-3 FFA ratio increased in NASH (P < 0.05).

CONCLUSIONS

NAFLD is associated with numerous changes in the lipid composition of the liver. The potential implications are discussed.

Similarities and differences in outcomes of cirrhosis due to nonalcoholic steatohepatitis and hepatitis C

The objective of this study was to prospectively define outcomes of cirrhosis due to nonalcoholic steatohepatitis (NASH) and compare them with those associated with hepatitis C virus (HCV) infection. We compared 152 patients with cirrhosis due to NASH with 150 matched patients with cirrhosis due to HCV. Over 10 years, 29/152 patients with cirrhosis due to NASH died compared with 44/150 patients with HCV (P < .04). This was mainly due to the lower mortality rate in patients with Child class A cirrhosis due to NASH versus HCV (3/74 vs. 15/75; P < .004). There were no significant across-group differences in mortality in patients with Child class B or C cirrhosis. Sepsis was the most common cause of death in both groups; patients with NASH had a higher cardiac mortality (8/152 vs. 1/150; P < .03). Patients with Child class A cirrhosis due to NASH also had a significantly lower risk of decompensation, defined by a 2-point increase in Child-Turcotte-Pugh score (P < .007). Cirrhosis due to NASH was associated with a lower rate of development of ascites (14/101 vs. 40/97 patients at risk; P < .006). NASH also had a significantly lower risk of development of hepatocellular carcinoma (10/149 vs. 25/147 patients at risk; P < .01). In conclusion, compensated cirrhosis due to NASH is associated with a lower mortality rate compared with that due to HCV. It is also associated with a lower rate of development of ascites, hyperbilirubinemia, and hepatocellular carcinoma. However, cardiovascular mortality is greater in patients with NASH.

A pilot study of vitamin E versus vitamin E and pioglitazone for the treatment of nonalcoholic steatohepatitis

BACKGROUND & AIMS

Insulin resistance and oxidative stress contribute to the pathogenesis of nonalcoholic steatohepatitis (NASH). We conducted a pilot study for the following reasons: (1) to test the hypothesis that a combination of an antioxidant (vitamin E) and an insulin sensitizer (pioglitazone) would be superior to vitamin E alone for the treatment of NASH, and (2) to define the effects of these interventions on insulin-sensitive metabolic functions and correlate the effects with changes in liver histology.

METHODS

A randomized prospective trial was performed to compare the efficacy and safety of vitamin E alone (400 IU/day) vs. vitamin E (400 IU/day) and pioglitazone (30 mg/day) in nondiabetic, noncirrhotic subjects with NASH. Metabolic functions were assessed by a 2-step, hyperinsulinemic (10 and 40 mU/m2/min) euglycemic clamp.

RESULTS

A total of 10 patients were randomized to each arm. Two patients on combination therapy discontinued treatment; one because of pregnancy and the other because of hepatotoxicity. Treatment with vitamin E only produced a significant decrease in steatosis (mean grade, 2.2 vs. 1.4; P < .02). Compared with baseline, combination therapy produced a significant decrease in steatosis (mean, 2.3 vs. 1; P < .002), cytologic ballooning (1.3 vs. 0.2; P < .01), Mallory's hyaline (0.7 vs. 0.2; P < .04), and pericellular fibrosis (1.2 vs. 0.6; P < .03). Although vitamin E had no significant effects, combination therapy produced a significant increase in metabolic clearance of glucose and a decrease in fasting free fatty acid (FFA) and insulin. The decrease in fasting FFA and insulin independently predicted improvement in hepatic steatosis and cytologic ballooning.

CONCLUSIONS

A combination of vitamin E and pioglitazone produces a greater improvement in NASH histology. The improvement in steatosis and cytologic ballooning are related to treatment-associated decreases in fasting FFA and insulin levels.

Clinical and histologic spectrum of nonalcoholic fatty liver disease associated with normal ALT values

A retrospective study was performed to (1) characterize the clinical and histologic features of those with nonalcoholic fatty liver disease (NAFLD) and normal alanine aminotransferase (ALT) values, (2) compare the spectrum of NAFLD associated with normal versus elevated ALT levels, and (3) determine whether there were differences in the clinical or histologic spectrum of NAFLD between those with a low normal versus high normal ALT value. A total of 51 subjects with NAFLD and normal ALT were identified and compared with 50 consecutive subjects with NAFLD and elevated ALT. The major indications for liver biopsy in those with normal ALT were unexplained hepatomegaly (n = 21) and evaluation as a potential donor for living donor liver transplantation (n = 16). The 2 groups were comparable with respect to age, gender distribution, and ethnicity. Approximately 80% of cases in both groups had at least 1 feature of the metabolic syndrome, the major risk factor for NAFLD. The 2 groups were also comparable with respect to the grade of the individual histologic parameters of NAFLD. A total of 12 subjects with normal ALT levels had bridging fibrosis, whereas 6 had cirrhosis. Diabetes was the only factor independently associated with an increased risk of advanced fibrosis (bridging fibrosis or cirrhosis) by multivariate analysis (relative risk: 2.3, P <.01). The mean steatosis (1.6 vs. 2.16, P <.04) and perisinusoidal fibrosis scores (0.35 vs. 0.9, P <.049) were lower in those with low normal (<30 IU/L) ALT versus high normal ALT. However, the prevalence of advanced fibrosis was similar (5 of 15 vs. 13 of 36, respectively). In conclusion, (1) the entire histologic spectrum of NAFLD can be seen in individuals with normal ALT values, (2) the histologic spectrum in these individuals is not significantly different from those with elevated ALT levels, and (3) a low normal ALT value does not guarantee freedom from underlying steatohepatitis with advanced fibrosis.

Characterization of absorbable collagen sponges as rhBMP-2 carriers

For clinical use recombinant human bone morphogenetic protein (rhBMP-2) is soaked onto an absorbable collagen sponge (ACS) for bone regeneration. Therefore, loss of rhBMP-2 upon mechanical handling during implantation and a potential effect of the carrier on in vivo retention is of interest. The interactions between drug and carrier were looked at from the application mode and the amount of protein which can be mechanically expressed from the combination was investigated. The results indicated that rhBMP-2 binds to the collagen system. The most hydrophilic double extended homodimer showed the least binding affinity to ACS. By extending the waiting time between soaking and implantation, protein incorporation could be increased. In addition, the amount of rhBMP-2 which could be expressed was reduced by heavier ACS material and allowed for a shorter waiting period, especially at lower rhBMP-2 concentration. Crosslinking of ACS with formaldehyde led to reduced binding of rhBMP-2 to collagen either by direct hindrance of binding or reduction in swelling and number of binding sites available. Higher product pH or anion concentration enabled to increase rhBMP-2 incorporation but was limited by the potential precipitation of rhBMP-2. Despite a variety of chemical changes of ACS by ethylene oxide sterilization incorporation was not changed significantly. The in vivo release kinetics of 125I-rhBMP-2 from the collagen sponge were studied using a rat ectopic implant model. The ACS/rhBMP-2 systems tested demonstrated small, but significant differences in the in vivo retention of rhBMP-2. Consequently, it is important to have as little variability in pH, anion concentration, crosslinking and ACS mass as possible to achieve consistent or maximum binding and to avoid rhBMP-2 precipitation. Furthermore, these characteristics can be important for other in vivo applications.

Characterization of absorbable collagen sponges as recombinant human bone morphogenetic protein-2 carriers

For clinical use recombinant human bone morphogenetic protein-2 (rhBMP-2) is soaked onto an absorbable collagen sponge (ACS) for bone regeneration. Therefore, loss of rhBMP-2 upon mechanical handling during implantation and a potential effect of the carrier on in vivo retention is of interest. The interactions between drug and carrier were looked at from the application mode and the amount of protein which can be mechanically expressed from the combination was investigated. The results indicated that rhBMP-2 binds to the collagen system. The most hydrophilic double extended homodimer showed the least binding affinity to ACS. By extending the waiting time between soaking and implantation, protein incorporation could be increased. In addition, the amount of rhBMP-2 which could be expressed was reduced by heavier ACS material and allowed for a shorter waiting period, especially at lower rhBMP-2 concentration. Crosslinking of ACS with formaldehyde led to reduced binding of rhBMP-2 to collagen either by direct hindrance of binding or reduction in swelling and number of binding sites available. Higher product pH or anion concentration enabled to increase rhBMP-2 incorporation but was limited by the potential precipitation of rhBMP-2. Despite a variety of chemical changes of ACS by ethylene oxide sterilization incorporation was not changed significantly. The in vivo release kinetics of (125)I-rhBMP-2 from the collagen sponge were studied using a rat ectopic implant model. The ACS/rhBMP-2 systems tested demonstrated small but significant differences in the in vivo retention of rhBMP-2. Consequently, it is important to have as little variability in pH, anion concentration, crosslinking, and ACS mass as possible to achieve consistent or maximum binding and to avoid rhBMP-2 precipitation. Furthermore, these characteristics can be important for other in vivo applications.

HLA-DR antigens and properdin factor B allotypes in responders and non-responders to the Rhesus-D antigen

HLA-DRw6 incidence was high in male responders to the Rhesus-D antigen (50%) compared to male non-responders (15.4%), P less than 0.02, P corrected N/S, pregnancy immunized females (23.1%) and a random population (26%). No Bf allotype frequency differences were found among these four groups.